A peristaltic pump (roller pump) is a type of positive displacement pump used for pumping fluids contained within a flexible tube. A peristaltic pump can use a turning cam to place part of a tube under compression, closing or occluding a section of the tube, and forcing the fluid to be pumped to move through the tube. The tube reopens to its natural state after the passing of the cam. This pumping process may be referred to as peristalsis. Peristaltic pumps may be used in laboratory instrumentation, including sample preparation devices, analytic devices, and so forth. For example, peristaltic pumps may be used to move fluids in a clean or sterile environment without the disturbances resulting from shear forces. Further, it is often desirable to use peristaltic pumps to pump clean, sterile, or aggressive fluids because cross contamination with exposed pump components does not occur.